Filter for smokable articles



Oc't, 4, 1950 H. A. LEBERT 2,954,787

FILTER FOR SMOKABLE ARTICLES Filed April l, 1958 I5 Sheets-Sheet 1 fig- 2 fir-42, L;

H. A. LEBERT FILTER FOR SMOKABLE ARTICLES oct. 4, 1960 Filed April l, 1958 5 sheets-sheet 2 0d, 4, 1960 H. A. LEBERT 2,954,787

FILTER FOR SMOKABLE ARTICLES Filed April l, 1958 y 3 Sheets- Sheet 5 E g, /z

Utiit@ FILTER FOR SMOKABLE ARTICLES Herbert A. Lebert, Millbrae, Calif., assignor to Mac- Farland, Aveyard & Company, Chicago, Ill., a corporation of Delaware Filed Apr. 1, 1958, Ser. No. 725,535

Claims. (Cl. 1`31-208) velocity of tobacco smoke passing through the passageway area may be accelerated and heavy tars in the smoke may be removed from the smoke as a consequence of their impingement upon a barrier which confronts the downstream end of the venturi passageway area.

The majority of present day filter-tip cigarettes use cellulose tiilaments in varied amounts with various bindmarked contrast to the lg inch or less orifice herein used Vto create high velocity-impingement tar collection according to the principles of my invention as set forth in my Vearlier led copending application, Serial No. 662,049,

filed May 28, 1957, for Removal of Tar and Other Deleterious Substances' From Tobacco Smoke.

According to the present invention, a very important feature of the same involves the concept of manufacturing the tar removal structure from a strip of material s uch as paper and the like whereupon it is rolled into tubular form and may be adhesively secured in tubular form. By virtue of this construction, the iilter tip cost for a cigarette can be very greatly reduced since it is well known that cellulose which is the material most commonly used in filter-tip cigarettes is considerably more expensive than paper-like materials and the like which may be used in the'formation of the tar removal structure for a cigarette to form a filter-tip cigarette and the like according to features of the present invention.

lt is clear that conventional filter tips trap or collect such tar as they do stop by virtue of the maze formed by the tilaments and the circuitous path the smoke travels in passing along the length (approximately %6) of the filter tip.

In contrast to the above conventional filter tips, a length of material such as paper may be spirally wound after the length of material has been cut to a predetermined configuration which length of material is provided with a critical sized smoke orifice or venturi. By virtue of the particular configuration imparted to the length of material when it is wound, a tortuous smoke channel area is formed with the venturi in communication with the channel area. The length of material is also provided with tab structures so that one end of the tube may be closed. The `tortuous smoke channel area extends generally transversely of the tube and links the other peripheral area of 2,954,787 Patented Oct. 4, 1960 the tube with the internal cavity defined by the tube. When a suction force is applied to the open end of the tube, tobacco smoke may be drawn transversely through the tube by way of the tortuous smoke channel area into the internal cavity area defined internally of the tube whereupon the smoke may be drawn out through the open end of the tube.

According to the pres'ent invention, an important object is to form the critical sized smoke passage vor venturi in the tortuous smoke channel area so that the venturi will operate to speed up the smoke to a terrific velocity exceeding, eg. ft. per second so that the heavy (high temperature formed) tar molecules `or particles will not be able to meander their way through the tortuous smoke channel area, but will, instead, impinge against and come to rest on the paper-like barrier that confronts or stands in their high speed, straight line path from the venturi. The lighter weight aromatic, low temperature formed smoke particles or fractions which go to make up a safe, enjoyable smoke will change their high speed straight line path in the barrier and thereby will be deflected away from the barrier through the channel area and out through the open end of the tube.

ln the past,`expansion cooling of tobacco smoke has been practiced and structures developed to attain this end have required Ian elongated expansion chamber for the smoke to expand which structure is conventional in the art. According to the present invention, the manufacturing cost of the .filter tip may be kept to a minimum since the expansion chamber is not required yand the dimensions of the conventional lter tip may remain substantially unaltered despite the inclusion of the critical passage area in the filter tip. In fact, if it is desired, the over-all length of the filter tip may be reduced without interference with the tar removal operation ofthe filter tip. Another advantage ofthe present invention kis that by manufacturing the tar removal structure from paper, the cost of the paper used in the tar removal structure will be reduced to approximately 50% of the Acost of the cellulose used in the conventional ilter tip.

lf the lilter tip construction is manufactured with an orifice or venturi area, for example, equivalent to an .028-.030 diameter hole, all the tars regarded harmful by modern medical thinking will be deposited that is, impinged on the filter tip filaments and thereby removed from the tobacco smoke.

.According to the practice of the principles of lmy invention, a length of paper-like material may be slit along a tortuous pathlongitudinally thereof while contemporaneously transversely cutting the length of material at suitable intervals to divide the strips into a series of lter tip lengths. During this same operation, the critical sized venturi passageway may be punched through -the blank.

Accordingly, an object of the resent invention is to provide a new and improved filter tip tar removal structure for cigarettes and the like.

Still another object of the present invention is to provide a new and improved lter construction for use with smokable articles which is highly economical.

Yet another object of the present invention is to provide a lter construction adapted rto be made by a method of manufacture which may be carried `out so as to enable etiicient large scale mass production of the same.

Other objects and features of the present invention will lmore fully become apparent in view of the following detailed description taken in conjunction with the accompanying drawings illustrating therein several embodiments and in which:

Figure l is a fragmentary diagrammatic plan view of a length of material showing the manner in which it may be cut to form a series of blanks;

Figure 2 is an enlarged side elevation of one of the blanks shown in a partially rolled or spiraled state;

Figure 3 is an enlarged' side elevation of the tar removal tubetor structure after it has been rolled to final form;

Figure 4 is an enlarged cross-sectional View taken substantially on the line IVwIV of Figure 3 looking in the direction indicated by the arrow;

Figure 5 is an enlarged cross-sectional view taken substantially on the line VwV of Figure 4 looking in the direction indicated by the arrows; v

-Figure 6 is a fragmentary cross-sectional view of a filter tip cigarette with the filter-tip similar to that shown in Figure 4 only with parts shown in elevation in Fig. 6;

Figure 7 is a fragmentary diagrammatic plan view of a length of stock cut to form blanks for a modified type of tar removal structure;

Figure 8 is a side elevation of the modified type of tar removal structure formed from one of the blanks shown in Figure 7;

Figure 9 is an end elevation of the modified typel of tar removal structure shown in Figure 8 as viewed from the closed end of the structure;

Figure l0 is an end elevation of the modified type of tar removal structure shown in Figure 8 as viewed from the open end of the structure;

Figure ll is an enlarged fragmentary cross-sectional view of a filter tip cigarette with the section through the tar removal structure being taken substantially on the line XI-XI of Figure 8 looking in the direction indicated by the arrows;

Figure l2 is a plan view of a 4blank of material for the formation of still another modified type of tar removal structure;

Figure 13 is a plan View similar to Flgure 12 only showing the blank partially rolled;

Figure 14 is a side elevation of the still another modified type of tar removal structure;

Figure 15 is an enlarged fragmentary cross-sectlonal view of a filter-tip cigarette with the section of the .tar removal structure being taken substantially on'the line XV-XV of Figure 14 looking in the direction Indicated by the arrows; and v Figure 16 is an enlarged cross-sectional view taken substantially on the line XVI-XVI of Figure 14 looking in the direction indicated by the arrows. l

The numeral 10 in Figure l indicates generally a strlp of material which has been longitudinally slit along` a tortuous path 11 with the tortuous path 11 also including transverse slits 12 disposed transversely at intervals along the length of the strip 10 as indicated at 12. It is in this manner that the strip 10 is divided into a plurality of blanks 13 which are adapted to be folded into cigarette tar -removal structures as indicated at 14 1in Figure 3. The structures 14 each comprise a rolled, spiraled length of material. During the operation where- -in the length of material 10 is divided into a plurality of the blanks 13, the length of material is also punched as indicated at 15 to provide each of the blanks 13 with a critical sized orifice orventuri which will be discussed at length at a later point herein with regard to the operation of the tar removal structure 14. When the blanky 13 is folded, the venturi orifice opens in a radially inward greater vertical dimension than the tab 17 with the excess material on the tab 16 comprising closure flap portion 16a. Also, the venturi 15 is disposed on the tab 16.

To form the tobacco tar removal structure 14 to proi- `vide a tubular, hollow chamber closed end body, the

blank is rolled and spiraled beginning at the end of the blank which is in closest proximity to the tab 17 and as shown in Figure 2. As is apparent in Figure 1, a recessed area 18 is disposed between the tabs 16 and 1 so that as the blank 13 is rolled, there is provided a slight radial gap as indicated at 19 in Figure 5 between the tab l17 and the venturi 15 in the tab 16. The area of the tab 17 which is disposed directly opposite and in radially confronting relation to the venturi 15 constitutes Ia radially outwardly facing impingement barrier or a paper barrier and is indicated at 20. The assembly of the tar removal structure -14 may be completed by continuing to roll the blank in the manner shown in Figure 2 until the blank has been rolled along its entire length with end flap 21 being adhesively secured in place at 22 by a suitable material such as glue and the like. With regard to the end flap 21, it will be noted that its height is such that top edge 21a is disposed below the level of the venturi 15, whichis significant for reasons that will hereafter become apparent. After the end fiap 21 has been secured in place, the area of the flap 16 projecting above the flap 17 comprising the closure flap 16a is folded over as indicated to form a flap closure 23 at one end of the tobacco 4tar removal structure 14. The closure iiap 16a may be suitably secured in place by means of glue and the like which is indicated generally at 24.

The tobacco tar removal structure 14 is shown telescoped inside of an outer sleeve 25. The outer sleeve 25 is also engaged over one end of -a cigarette indicated generally at 26 with the end of the cigarette abutted against the closure end 23 of the tobacco tar removal structure 14. It is in this manner that a filter-tip cigarette 27 may be manufactured.

The tobacco tar removal structure 14, as hereafter described in greater detail, is provided with a smoke passage or channel area 28 through which the tobacco smoke may pass. The area 28 when the structure 14 is mounted in assembly with the cigarette 26 includes a smoke col- Y lection chamber 29 pro-vided ybetween the outer tubular sleeve 2.5 Iandthe radially outer peripheral surface of the flap 16. The smoke collection chamber preferably has a reduced thickness in the order of .C110-.015 inch so that particles of tobacco may not be readily drawn into the smoke collection chamber 29.V After the filter-tip cigarette 27 has been ignited, by applying a suction force to the open end of the sleeve 25 and the cigarette tar removal structure 14, smoke may be drawn into the collection chamber 29 and then through the critical sized orifice 15 whereupon tars T may be impinged against the impingement barrier 20 and with the gap 19 providing a tar collection sump `for the collection of the heavy tars removed from the tobacco smoke. The tobacco smoke after it has struck the impingement barrier 20 will be deflected Iaxially or longitudinally of the venturi 15 toward the closed end 23 of the structure 14. By virtue of the fact that the closed end 23 of the structure 14 is spaced axially from edgev 17a of vthe iiap 17, a radially extending annular gap .30 is created which allows the deflected smoke to pass upstream of the venturi `15 and then radially of the tab 17 through the radial gap 30 and then axially or longitudinally toward the open end y0f therfilter tip into the mouth of the smoker by a tubular cavity 31 4which is peripherally defined by the spiraled length of material and more particularly by the radially inner surface of the flap 17.

The channel area 2SV inthe structure 14 is partially defined by the flap closure 23, and rfurther includes the orifice 15, the gap 19,the gap Sti'and the cavity 31. When the structure 14 is mounted in assembly with the cigarette 26, the end surface of the cigarette cooperates with the flap closure 23 and the radially outer surface of the tab 16 cooperates with radially inner surface of the sleeve 25 to define the smoke collection chamber 29l and to'fu'rther define/the channel area 28.

etc. In the structure of the present invention, this problem. is overcome by providing the venturi orifice or passageway which greatly increases the velocity of smoke stream passing through the filter tip so that when the stream strikes the barrier, the tar is lodged and collected upon the peripheral surface of the paper or other suitablematerial and the resulting purified smoke alters its course through the structure and passes on to the smoker through the downstream end of the filter tip. By referring to the removal of tare, the term tars should be regarded as embracing tars, resins, and other harmful substances. While there will be variations in the size of the o-riice, depending upon the character of the smoke, the density of the cigarette mass, etc. in general effective results are obtained when the orifice diameter is from .025 to .038 (square inch areas of .0005 to .001). Very satisfactory results have been obtained where the orifice diameter is .028 inch to .032 inch (.0006 to .0008 square inch). As a preferred example, I have employed effectively an orifice having a diameter of .030 (.0007 square inch), lwhich gives excellent tar removal and ease of drawing.

The critical orifice size is correlated with the impingernent barrier which is located as close as pos-sible to the orifice or venturi outlet consistent with the free flowing of the collected t-ars; i.e., without impairing the flowing of the tar away from the point of impingement. In practice, I yhave found that a satisfactory range is a distance of .005 .to .030. In the specific example referred to, the impingernent barrier is preferably spaced from the orifice or Venturi 15 by 3%;4 of an inch (.015), or approximately one-half the orifice diameter.

The operation resulting from the structure shown herein is in contrast to the operation of cooling devices heretofore employed with cigarettes or cigarette holders. Such cooling devices bring about a peripheral cooling of the smoke. but allow substantial core portions of the tars to pass onto the smoker. In my structure, the entire cross-section of the smoke stream is subject to the action of the impingernent area 20 so that the tars T and other harmful particles are removed by the foregoing high velocity impingement action upon the barrier 20.

The slight spacing between the outlet of the orifice and. the barrier enables the smoke stream to reach the barrier with substantially undiminished speed, while at the same time enabling the purified smoke to change direction,` whereas tar fractions, by reason of their high inertia, cannot change direction and therefore deposit on the first surface contacted. If paper is used as the material for the formation of the cigarette tar removal structure 14, the tars T will. impregnate a substantial area of the tab 17 by a capillary action depending on the absorbency of the paper. If the paper is relatively nonabsorbent then the tars will appear in greater concentration for viewing by the smoker.

l Shown in Figures 7-ll is a modiiied form of my invention wherein a length of material 110 has been slit along la tortuous path 111 and 112 in a manner similar to that. in the first form of my invention to form a series of blanks 113 which blanks are adapted to be spirally wound to form tobacco tar removal structures such as is indicated at 114. Each of the structures 14 comprises a rolled, spiraled length of material. In the formation of the blanks 113, each of the blanks is provided with a radially inwardly opening critical sized orifice or orifice area or venturi 115 on one of its tabs 116 and 117. The orifice 115 is again formed on the tab (tab 116) having the greater vertical dimension and which tab includes closure ap portion 116e. An impingement barrier 120 is provided on the tab 117 and faces radially outward toward the radially inwardly opening venturi orifice area 115.

In the present instance, the configuration of the tabs 116 and 117 has been modified as is most clearly illustrated in Figure l1. To this end it will be noted that the tab 117 is of sufficient vertical ydimension so that it may be bent over forming a flap portion 117a. The ap portion 117:1 may be adhesively secured to the portion of the iiap 116 which has been folded over to form a closure 123 to close one end of the cigarette tar removal structure 114. A suitable adhesive 124 (Figure ll) such as glue may be utilized to secure the folded over closure portions 116a of the tab 116 in place to form the closure 123.V In the spiral winding of the blank 113, end flap 121 may be secured to the underlying layers of paper by a suitable adhive 122 to complete the formation of the tar removal structure 114.

A tubular filter tip sleeve 125 has a cigarette 126 lodged or telescoped therein at one end and the tobacco tar removal structure 114 is telescoped into the sleeve at the opposite end with the closed end 123 of the str-'ucture 114 abutted against one end of the cigarette i126 thereby forming a filter tip cigarette 127. The tobacco tar removal structure has a channeled area or passage area 128 to aid in the passage of smoke through the sleeve 125 and the tar removal structure 114. By virtue of the fact that the tab 116 only extends` approximately one revolution and further by reason of the fact that it is disposed upstream of end flap 121 as` well as its top edge 121:1, one end of the tobacco tar removal structure has a reduced diameter so that when the structure 114 is in assembly with the outer sleeve 125, a smoke collection chamber 129 is created between the venturi 115 and the outer sleeve 125. This chamber is a portion of the passage area 128 and should have a dimension similar to that described in the iirst form of the invention so that tobacco particles will not become lodged therein. After the smoke passes into the smoke collection chamber `129, upon a suction force being applied to the open end of the sleeve 125 of the filter cigarette 127, the smoke is then drawn through the venturi with the tar particles being impinged upon the barrier `and then being deflected circumferentially with respect to the tab 117 so that the purified smoke may then pass longitudinally upstream through a tubular cavity 131 defined by the structure 114 into the mouth of the smoker. In this respect, it should be noted that the dimension of the tab 117 is such that it comprises a relatively small arcuate segment when the structure 114 is in final assembly so that the smoke is free to pass into the internal cavity 131 of the structure 114.

The channel area 12S is similar to the channel area 28 except that the smoke after striking tab 117 is deflected circumferentially into cavity 131 and need not iiow axially upstream of the venturi 115 as in the first form of the invention.

The size ofV the orifice and the spacing between the orifice and the barrier 120 may be of the same order as previously described and the operation of this modification is substantially the same as that previously described.

Shown in Figures 12-16 is a third form of my inven. tion wherein a blank 213 is illustrated in Figures 12 and 13 which blank may be formed by slitting la length of material along a tortuous path in much the same manner as the blanks previously described were formed in the other forms of my invention.

The blank 213 when folded into tubular form comprises a tobacco tar removal structure 214. The structure 214 comprises a rolled, spiraled length of material. The blank 213 has a smoke entry slot 215 disposed on tab structure 216. The tab structure 216 is provided with a fold over closure flap portion 21611. In this instance as compared to the prior forms of my invention only a single enlarged tab is utilized.

Also provided on the tab structure is a vertical venturi passage or slot area 217 and a smoke exit slot 218. The slots 215 and 218 are spaced from the venturi passage area or orifice area 217 on its opposite sides with'the slot 215 being in horizontal alignment with the upper end of the venturi passage area 217 and with the slot 218 being in horizontal alignment with the lower end of the venturi passage area 217. The venturi passage crossf sectional area may vary in accordance with the dimensional relationship previously set forth with excellent results being attainable through the use of a venturi cross-sectional passage area of .0007 square inch. This .0007 square inch dimension may be provided through the use of paper having a .010" thickness and with the venturi area 217 having a .070" width.

To form the structure 214, the blank 213 is` rolled and spiraled beginning at the end of the blank where the tab structure 216 extends yout to the end of the blank. In Figure 13 the blank is shown partially rolled showing how the slots 215 and 218 are particularly related with respect to the upper and the lower ends of the venturi area 217 and Figure 14 shows the blank 213 completely rolled with the closure ap area 216:1 folded over forming a tube closure 223. To sustain the slots 215 and 218 in alignment with the venturi orifice 217, end fiap-221 is secured in place by adhesive 222 and the closure `fiap 216a is secured in position by the adhesive 224 (Figure 15). It will be noted that when the blank is in fiat form a paper barrier orventuri or impingement barrier area 220 is provided which comprises the bottom edge of the venturi orice area 217 as well as a portion of the edge defining the slot 218 so that tar may be impinged thereagainst and allowed to ow internally of the tubular structure 214,

In Figure l5, the structure 214 is shown telescoped inside of an outer sleeve 225. The outer sleeve is also engaged over one end of a cigarette 226 with the cigarette abutted against the closure 223 thereby forming a filter.

tip cigarette 227.

The filter tip cigarette 227 is provided with a channel area 228 through which the tobacco smoke may pass in-A cluding a smoke collection chamber 229 as well as the slots 215 and 218 and the Venturi orifice or passage area 217. The chamber 229 is defined between the upper flap edge 221a and the cigarette and between the inner surface of the sleeve 225 and the outer surface of the tab structure 216. The area 228 is similar to the channel area 28 except that flap 223 abuts against the cigarette and a slot 218 is provided to permit the smoke to flow from the Venturi orifice area 217 into a cavity 231. A Smoke may pass through the cigarette 226 into the chamber 229 and then through the slot into the venturi orifice 217 whereupon the tars T will be removed from the smoke lafter passing across the slot area 217 as they are impinged upon the barrier 220 disposed at the axially downstream end of the orifice area 217. The purified smoke after striking the barrier 220 will be deflected radially or transversely of the paper and will pass through the slot 218 into an internal cavity 231 and then out through the open end of the structure 214 into the mouth of the smoker. The tar will be urged through the slot 218 after striking the barrier 220 and will collect along the wall of the cavity 231 adjacent to the slot 218.

In all forms of my invention,A if paper is used fas the material for the tar collection structure, the cost of material may be reduced by about one-half as compared to the cost of material for the cellulose acetate used in conventional filter tip cigarettes. Through the use of the velocity impingement principle approximately 40% of the tars including a very high percentage of the more dangerous high temperature tars maybe removed from the smoke which is about four times the amount removed by conventional filters. l

It will be understood that modifications and variations may be effected without departing from the scope of the noyel concepts of the present invention.

l claim as my invention:

l.v In a filter for use with a smokable article. a tubular body formed lfrom a spirally wound strip of thin material of predetermined varying width along its length and providing a chamber within the body, the outer periphery of the body being longitudinally -stepped with one end portion being stepped-in to a reduced diameter, a marginal extension portion of the strip at the extremity of said one end portion of the body being turned over and constituting a closure across such end of the body, said stepped-in one end portion having a smoke passageway extending inwardly therethrough spaced from said closure and affording a smoke-accelerating orifice inwardly relative to said stepped-in portion, an inner winding of said strip providing an impingement barrier in slightly spaced confronting relation downstream relative to said orifice, said inner winding being spaced at its inner endy from said closure and thereby providing a smoke passageway extending laterally from said barrier and into said chamber, said body having a smoke outlet from the end portion thereof opposite to said closure.

2, A filter as defined in claim 1, wherein the thin material comprises paper having a thickness substantially equivalent to the space between the orice and said rimpingement barrier, with one of the windings of the body spacing a winding defining said stepped-in periphery por tion and having said orifice therethrough from said inner winding constituting said part of the strip providing the impingement barrier.

3. In a filter for use with a smokable article, a tubular body formed from a spirally wound strip of thin material of predetermined varying width along its length and providing a chamber within the body, the outer periphery of the body being longitudinally stepped with one end portion being stepped-in to a reduced diameter, a marginal extension por-tion of the strip at the extremity of said one end portion of the body being turned over and constituting a closure `across such end of the body, said vstepped-in one end portion having a smoke passageway extending inwardly therethrough spaced from said closure and affording a smoke-accelerating orifice having a cross-sectional flow `area of .0005 to .001 sq. in. inwardly relative to said stepped-in portion, a part of said strip providing an impingement barrier in spaced confronting relation about .005 to .030 inch downstream relative to said orifice, there being a smoke passageway extending laterally from said barrier and into said chamber, said body having a smoke outlet from the end portion thereof opposite to said closure.

4. A filter as defined in claim 3, wherein said stepped- 4in one end portion of the body comprises three windings of said strip with the `mwardly extending smoke passageway being in the outermost and the intermediate of the windings, said orifice being in the intermediate of said windings, said intermediate winding having said impingement barrier, and the innermost of the windings having said smoke passageway extending laterally from the barrier. 5. In a filter for use with a smokable article, a tubular body formed from a spirally wound strip of thin material of predetermined varying width along its length and providing a cha-mber within the body, the outer periphery of the body being longitudinally stepped with one end portion being stepped-in to a reduced diameter, a marginal extension portion of the strip at the extremity of said one end portion of the body being turned over and constitu-ting a closure across such end of the body, said stepped-in one end portion having a smoke passageway extending inwardly therethrough spaced from said closure and affording a smoke-accelerating orifice inwardly relative to said stepped-in portion, a part of said strip providing an` impingement barrier in slightly spaced confronting relation downstream relative to said orifice, there being a smoke passageway extending laterally from said barrier and into said chamber, said body having a smoke outlet from lthe end portion thereof opposite to said closure, and a mouthpiece sleeve engaging the largest diameter portion of the periphery of the tubular body and extending to a substantial length beyond said closure, the wall of lthe sleeve about said stepped-in peripheral portiOr! Qf the body defining with said stepped-in portion a 9 smoke collection chamber from which said inwardly exftending smoke passageway leads.

References Cited in the le of this patent UNITED STATES PATENTS `851,773 Pfortner Apr. 30', 1907 1,594,606 Clivio Allg. 3; 1926 1,996,990 Cullen Apr. 9, 1935 10 Segal Mar. 10, 1936 Lange Jan. 18, 1938 Todor-off Nov. 7, 1939 Brothers June 20, 1950 Brothers Sept. 25, 1956 FOREIGN PATENTS Germany v May 22, 1903 Great Britain Nov. 7, 1956 

